The study of floral ontogeny in Glycyrrhiza glabra L.

Glycyrrhiza glabra L. is a perennial herbaceous plant, belonging to the family Fabaceae and subfamily Papilionoideae. Comparative floral ontogeny is important for better understanding of floral evolution within the subfamilies of Fabaceae. The aim of this study was to present a complete ontogenetic pathway of G. glabra, as a member of tribe Galegeae and to compare it with other studied species of the Papilionoideae. For this purpose, flower buds of different ages were collected and then fixed in FAA. After a fixation period of 24 h, the samples were rinsed and after dissection the samples were dehydrated in sequential ethanol concentrations of 70% and then 95%. The samples were stained with 0.5% nigrosin black in ethanol. The more remarkable features of flower ontogeny were the abaxial-adaxial unidirectional initiation of organs primordia within each floral whorl, high overlap in the time of initiation of whorls and early carpel primordium initiation. The overlapping in time of organ initiation and precocious inception of carpel were advanced characters that were previously reported in the members of inverted repeat lacking clade (IRLC) of Papilionoideae. However, lacking common primordium was the character that distinguished G. glabra from other studied species of IRLC.